5 - Astronomy Flashcards
Explain how/why the weight & value of g differ between the Earth’s surface and the surface of other celestial bodies
The weight depends on the gravitational field strength
- The larger the mass of the body, the stronger its gravitational field
- The Earth is more massive than the Moon, therefore objects weigh more on the Earth’s surface than the Moon
Name all the planets in our Solar System in order from the sun
Sun
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
What can you find in our Solar System that aren’t planets?
Dwarf planets (Pluto, Eris)
Asteroid
Comets
Man made satellites
What was the Geocentric Model?
Suggested the Sun, Moon and other planets orbited the Earth in perfect circles
What is the Heliocentric Model?
Suggested the Sun was at the centre of the Solar System
Why was the Geocentric Model like that?
People on Earth didn’t have telescopes & could only see the sun and moon rising and setting in the same way every day
Model was accepted from Ancient Greece - about 1500s
What was the evidence for the Heliocentric Model?
When looking at Jupiter through a telescope, Galileo noticed some stars orbiting Jupiter (they never moved away), showing not everything orbited the Earth – evidence of the Geocentric Model being wrong
What is the Steady State theory?
Matter is always being created
- Universe has always existed & always will no (no beginning or end)
- As universe expands, new matter is created
What is the Big Bang theory?
All matter was originally in a very small, hot, dense ball which then “exploded” & started expanding space
- Gives an age for the universe : ~14 billion y
What is CMBR, and which theory is it evidence for?
Cosmic Microwave Background Radiation - low frequency electromagnetic radiation coming from all parts of the universe
- shows the universe was once much hotter & denser, -> universe had a beginning -> big bang theory
